1. Field of the Invention
This invention relates to a printing group of a rotary roller printing machine, preferably a Rotogravure Rotary Roller Printing Machine, with a printing cylinder that is dipped into a dye vat and whose shaft journals can be supported on support devices, preferably supporting rolls, for the purpose of exchanging the printing cylinder.
2. Description of the Related Art
After the printing order has been finished, the printing cylinder of a printing group or the printing cylinders of the printing groups of a Rotogravure Rotary Roller Printing Machine must be taken out and must be replaced for the next printing order by correspondingly altered printing cylinders. Here, an effort is made to perform the required refitting work in the shortest possible time in order to reduce the unproductive idle times of the printing machine. To change a printing cylinder, the latterxe2x80x94after separation of the bearings holding its shaft journalsxe2x80x94is usually supported on supporting rolls over segments of its shaft journal, from which the printing cylinder is then removed, for example, via hoisting and transport devices, and upon which an exchanged printing cylinder is then placed. EP 0 980 312 A1 discloses a printing group of the kind mentioned initially where, for the purpose of changing the printing cylinder, one must place one of the support rolls that support shaft journals, in a second position.
The object of the invention is to create a printing group of the kind mentioned initially where the printing cylinder can be exchanged in a simple and quick manner.
This problem is solved according to the invention in the following manner. Each support device is arranged on a horizontally movable beam that is provided with a drive, via which one can shift the support devices between the bearings of the printing cylinder and an extended position in which there is provided a device that lifts out and inserts the printing cylinder.
In the printing group according to the present invention, the printing cylinder can be exchanged quickly and in a simple fashion by virtue of the following procedure. The printing cylinder that is to be exchanged and that rests on the support devices, can be run out by the horizontally movable beam so far out of the printing group that it can be deposited in a very easily accessible manner and for the purpose of its exchange, upon a lifting device that, in a corresponding fashion, can also be used for the insertion of the printing cylinder that is to be exchanged.
In a practical manner, the horizontally movable beams are racks that can be moved in guides. In the process, the racks can be driven by a shaft that bears the pinion gears which drive the racks.
The device that lifts and inserts the printing cylinders can consist of synchronized lifting and lowering bearings for the shaft journals. The latter can lift the printing cylinder off its support device and hold it, in which connection the printing cylinder can be lifted off the bearings by the usual hoisting and transport devices, for example, forklifts.
The guides and the drive for support bearings are in a practical manner arranged in a frame that is connected with the frame of the printing group.
The following is provided according to a particularly preferred embodiment. Two pairs of support bearings are arranged offset in term of height in each of two beams that can be lifted and lowered in the guides. This design of the invention makes it possible to house the printing cylinder to be exchanged in one pair of the support bearings and, in the other pair of the support bearings, to keep in readiness the printing cylinder that is to be newly installed, so that the exchange can be done briskly and so that the exchanged printing cylinder can be taken out, while the other one is moved into its operating position or has thus been moved.
If the printing cylinder only, and not also the pertinent dye vat, is to be exchanged, then the dye vat is lowered so that the printing cylinder can be run out horizontally without being obstructed by the dye vat. Another feature of the invention provides the following, for this purpose. The dye vat is retained on a vat carrier that can be lifted and lowered in the printing machine frame. The drive of the vat carrier can consist of a pinion gear and rack drive. In a practical manner, the vat carrier is retained in a horizontally movable fashion in a guide device that can be lifted and lowered in the printing machine frame so that, via such carrier, the dye vat can also be run out of the printing group for the purpose of exchanging it.
It is frequently required to exchange the printing cylinder and at the same time also its dye vat so as to coordinate their formats with each other. To meet this requirement, another feature of the invention provides for the following. In its raised position, the dye vat can be coupled to the horizonally movable beam so that it can be run out and run in together with the printing cylinder.
In a practical manner, the beam is equipped with a clutch rod that is provided with a groove or borehole which, in the raised position of the vat carrier, engages a pin or peg that is connected with the vat carrier.
According to a preferred embodiment, the following is provided so that the dye vat and the pertinent printing cylinder can also be exchanged in a simple manner and quickly. The beams, that can be lifted and lowered, are provided, under the support bearing or the support bearings for the printing cylinders, with a support bearing or support bearings for the dye vat or the dye vats.